4 Answers

Well, it very much depends on your budget and some other factors.
You can run CADD pretty smoothly on a machine with an i5 (Ivy or Sandy, a few to choose from) and a FirePro V4900 for medium sized projects. An 8GB of RAM and that's pretty much it. Other parts don't matter as those.
You can consider overclocking on air, multiple monitors setup, etc ...

My new to-be-built machine will cost me about $1,600 for only the case and internal components, you can get a workstation cheaper with the previous spec's for around $1,000-$1,200.

When you want to start planning the parts, you can contact me and I'll help you.

If you have a minimal budget, a second hand workstation is a good starting point. E.g. an HP XW6400 or Dell Precision 490 with dual Xeon 5160 CPU's, an nvidia quadro fx3500 graphics card and 6 - 8GB ram would be a very capable machine

I am an AutoCad tech at the University of Wyoming my work computer is just an old dell t5400 the thing that will help any computer running AutoCAD run faster is to run Windows XP it just seems to handle it better.
Another option that has worked for me is just a toshiba satelite with a 4g ram but adding 4g ram with ready boost.

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